There are many situations where environmental authorities use a mix of environmental policy instruments, rather than one single instrument, to address environmental concerns. For example, one instrument may be used to reduce overall emissions of a pollutant while another is used to address specific seasonal concerns. Very little work has been done on the economic impacts of the application of multiple instruments. This paper investigates the unintended impacts of the interaction of a tradable permits scheme with direct seasonal regulations on the rate of adoption of advanced abatement technologies.